Metal end having fluted end curl

Abstract

A loose metal end for forming a seamed can end closure and which includes an annular marginal seaming panel having a radiused outer rim concluding in a curled end underlying the seaming panel and provided with a peripherally interspaced array of radially extending flutes shaped to crest directionally towards the seaming panel. When double-seamed onto a can body, the fluted curled end is folded into a fluted hook end with the flutes cresting radially outward and away from the can body. As thus disposed, the flutes provide preselectively located sites which function to direct such "pinwrinkles" or "pinlips", as may result from buckling compressive forces generated in the hook end during the seaming or crimping operations, to project radially outward and away from the can body.

I claim: 
     
       1. A loose metal can end for use in forming a seamed can end closure for a can body, said loose metal can end including a central panel marginally encompassed by a marginal seaming panel having a peripherally depending curled outer rim defining a convexly radiused cross-sectional configuration and concluding in a radially inwardly curled end, said curled end including means preformed therein for inducing said curled end to pinwrinkle directionally away from said can body when said loose metal can end is subsequently seamed onto the end thereof, said means comprising a peripherally interspaced array of flutes respectively cresting directionally towards the interior confines of said outer rim, and said curled end with the exception of said flutes being otherwise essentially smoothly surfaced throughout the peripheral entirety thereof. 
     
     
       2. A loose metal can end as defined in claim 1, wherein said flutes are substantially equally interspaced and substantially identically shaped. 
     
     
       3. A loose metal can end as defined in claim 1, wherein said outer rim defines a generally toric peripheral configuration having an essentially uniform maximum outer diameter. 
     
     
       4. A loose metal can end as defined in claim 3, wherein the number of flutes in said curled end is not less than 9 flutes per inch of maximum diameter of said outer rim. 
     
     
       5. A loose metal can end as defined in claim 4, wherein said flutes have a height dimension which is in the range of about 0.75 and 1.25 times the metal thickness of said loose metal can end. 
     
     
       6. A loose metal can end as defined in claim 5, wherein said outer rim is uniformly radiused and wherein said flutes have a length dimension in the range of about 1.0 to about 1.3 times the dimensional radius of outside curvature of said outer rim. 
     
     
       7. A loose metal can end as defined in claim 3, wherein the number of flutes in said curled end is between about 9 and 15 flutes per inch of maximum diameter of said outer rim. 
     
     
       8. A loose metal can end as defined in claim 3, wherein the number of flutes in said curled end is between about 10 and 12.5 flutes per inch of maximum diameter of said outer rim. 
     
     
       9. In the combination including a hollow can body having an axially extending body wall terminating in an outwardly flanged rim surrounding said body wall, a can end closure double-seamed with said flanged rim and closing the end of said can body, said can end closure having a marginal seaming panel comprising an outer seaming wall integrally interconnecting with an inner seaming wall disposed in substantially concentrically interspaced relationship within said outer seaming wall, said outer and inner seaming walls being radially constricted and sandwiching said flanged rim tightly therebetween in hermetically sealed and interlocking seamed relationship, the improvement wherein said inner seaming wall of said can end closure includes means preformed therein for inducing pinwrinkles caused by subsequent constriction of said inner seaming wall to project directionally away from said can body, said means comprising a peripherally interspaced array of flutes defined in said inner seaming wall and respectively cresting directionally towards said outer seaming wall, and said inner seaming wall being essentially smoothly surfaced between each of said flutes. 
     
     
       10. The combination as defined in claim 9, wherein said can body is a laminated fiber-type can body.